diff --git a/app/assets/javascripts/graphql_shared/queries/project_autocomplete_users_with_mr_permissions.query.graphql b/app/assets/javascripts/graphql_shared/queries/project_autocomplete_users_with_mr_permissions.query.graphql
index 8155451fb7cef46862911d753c20947f5622a37a..854842839eb3238329a5fa9c4f7f0041137fae48 100644
--- a/app/assets/javascripts/graphql_shared/queries/project_autocomplete_users_with_mr_permissions.query.graphql
+++ b/app/assets/javascripts/graphql_shared/queries/project_autocomplete_users_with_mr_permissions.query.graphql
@@ -11,6 +11,7 @@ query projectAutocompleteUsersSearchWithMRPermissions(
     users: autocompleteUsers(search: $search) {
       ...User
       ...UserAvailability
+      compositeIdentityEnforced @gl_introduced(version: "18.7.0")
       mergeRequestInteraction(id: $mergeRequestId) {
         canMerge
       }
diff --git a/app/assets/stylesheets/page_bundles/merge_requests.scss b/app/assets/stylesheets/page_bundles/merge_requests.scss
index f7eb44bb6bbd7db263e6da254f02a5d95b2c946b..7295e52503455c2eb007192918d91ef705aa7e3c 100644
--- a/app/assets/stylesheets/page_bundles/merge_requests.scss
+++ b/app/assets/stylesheets/page_bundles/merge_requests.scss
@@ -975,3 +975,16 @@ $diff-file-header-top: 11px;
 .merge-request-review-drawer .rte-text-box{
   line-height: 1.5;
 }
+
+/* stylelint-disable-next-line gitlab/no-gl-class */
+.gl-new-dropdown-item:has(.sidebar-reviewer-disabled) {
+  cursor: not-allowed;
+}
+
+.sidebar-reviewer-disabled {
+  /* stylelint-disable-next-line gitlab/no-gl-class */
+  .gl-font-bold,
+  .gl-text-subtle {
+    color: var(--gl-text-color-disabled);
+  }
+}